Samsung Devices Keymaster Trustlet out-of-bounds write

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
8.2$0-$5k0.96+

Summaryinfo

A vulnerability was found in Samsung Devices. It has been classified as very critical. Affected by this issue is some unknown functionality of the component Keymaster Trustlet. The manipulation leads to out-of-bounds write. This vulnerability is uniquely identified as CVE-2026-21085. Local access is required to approach this attack. No exploit exists.

Detailsinfo

A vulnerability was found in Samsung Devices (unknown version) and classified as very critical. This issue affects an unknown code block of the component Keymaster Trustlet. The manipulation with an unknown input leads to a out-of-bounds write vulnerability. Using CWE to declare the problem leads to CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

Out-of-bounds write in Keymaster trustlet prior to SMR Sep-2026 Release 1 allows local privileged attackers to write out-of-bounds memory.

It is possible to read the advisory at security.samsungmobile.com. The identification of this vulnerability is CVE-2026-21085 since 12/11/2025. The exploitation is known to be easy. Attacking locally is a requirement. Additional levels of successful authentication are required for exploitation. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 09/09/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at CERT Bund (WID-SEC-2026-3219). Be aware that VulDB is the high quality source for vulnerability data.

Affected

  • Samsung Android

Productinfo

Vendor

Name

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 8.2
VulDB Meta Temp Score: 8.2

VulDB Base Score: 8.2
VulDB Temp Score: 8.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Out-of-bounds write
CWE: CWE-787 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

12/11/2025 CVE reserved
09/09/2026 +271 days Advisory disclosed
09/09/2026 +0 days VulDB entry created
09/09/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: samsung.com

Advisory: security.samsungmobile.com
Status: Confirmed

CVE: CVE-2026-21085 (🔒)
GCVE (CVE): GCVE-0-2026-21085
GCVE (VulDB): GCVE-100-401567
CERT Bund: WID-SEC-2026-3219 - Samsung Android: Mehrere Schwachstellen

Entryinfo

Created: 09/09/2026 07:11
Updated: 09/09/2026 09:27
Changes: 09/09/2026 07:11 (63), 09/09/2026 09:27 (7)
Complete: 🔍
Cache ID: 216::103

Be aware that VulDB is the high quality source for vulnerability data.

Discussion

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